- Scientific note Bangladesh J. Zool. 45(1): 97-100, 2017 ISSN: 0304-9027 (print) 2408-8455 (online)

OCCURRENCE OF A HUNTSMAN OLIOS LAMARCKI LATREILLE, 1806 (ARANEAE: : SPARASSIDAE) FROM NIJHUM DWIP, BANGLADESH

Muntasir Akash*, Nusrat Jahan and Mahatub Khan Badhon

Department of Zoology, University of Dhaka, Dhaka-1000, Bangladesh

While conducting a biodiversity survey in deltaic island clusters of South- Central Bangladesh, a spider was encountered on December 08, 2016 from a backyard garden of Nijhum Dwip (22°04′21.78″N 91°01′48.02″E, Figs 1-2). The specimen was examined, photographed and identified as a sparassid species Olios lamarcki Latreille, 1806. This is the first confirmed documentation of O. lamarcki to the spider inventory of Bangladesh. The sparassid genus Olios is the most diverse in the family, characterized by upraised and dome-shaped prosoma; indistinct to no-groove on thorax; longer second pair of legs; elongated and broadened mouth appendages i.e., clypeus and labium; distinctive eyes with straight anterior rows, procurved posterior rows and bigger and brighter anteromedians (Gravely 1931, Biswas and Raychaudhuri 2005, Platnick 2011). Typical of all araneomorph , Olios is with vertically oriented chelicerae (Foelix 2011). This genus, like other sparassids, is vernacularly known as Huntsman spider due to their wandering- stalking predation technique, and sometimes as Giant crab spider due to their size and appearance as well as for solitary, no-snare dependent nature (Isbister 2003, Foelix 2011). Of 246 species of this diverse tropical ‘taxonomic trash- basket’, three have been sighted from Bangladesh i.e., O. gravelyi Sethi and Tikader, 1988, O. hampsoni Pocock, 1901 and O. durlaviae Biswas and Raychaudhuri, 2005 - the last one being endemic to the country (Siliwal and Molur 2006, Ahmed et al. 2008, Platnick 2011). There was no record of O. lamarcki from Bangladesh till this finding, though it is among the 26 species of Olios documented from neighbouring India (Keswani et al. 2012). However, this discovery is also an eastern-most record of this species for both the Indian sub- continent and South Asia, as latest confirmed sighting was from West Bengal, India (Gravely 1931).

*Author for correspondence: < [email protected]>. © 2017 Zoological Society of Bangladesh DOI: http://dx.doi.org/10.3329/bjz.v45i1.34199

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Fig. 1. Map showing the place of discovery.

Occurrence of a huntsman spider Olios lamarcki 99

Class Arachnida Lamarck, 1801 Order Araneae Clerck, 1757 Family Sparassidae Bertkau, 1872 Genus Olios Walckenaer, 1837 Species Olios lamarcki Latreille, 1806 (Plate 02)

Material examined: December 08, 2016, one female individual, Nijhum Dwip, Bangladesh, 22°04′21.78″N 91°01′48.02″E, coll. M. Akash and M.K. Badhon Meristic. Carapace length 1.07 cm, total body length 3.10 cm, leg span 7.03 cm. Taxonomic identification of the individual was made with thorough observation of morphological characteristics. Large sized spider. Distinctly elevated and convex cephalothorax with typical indistinct groove, rounded labium. Second pair of legs is the longest; girth of abdomen is greater than its length (Biswas and Raychaudhuri 2005).

Fig. 2. a. Live Olios lamarcki Latreille, 1806 found in Nijhum Dwip; b. Sketch of a vulva (inset, after Gravely 1931); c. Ventral side of the species (inset, after www.insecte.org).

O. lamarcki as having light gray prosoma with a faint cross and pale buff- golden convex opisthosoma with median black-colored patch along the middle. Legs had distinctive barring pattern, each with three black-speckled white bands and four alternating black bands; black band on metatarsi being the larger.

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Tibia of first pair of legs was with two pairs of small spines. Ventrally, the species shows uniform bands on leg same as of dorsal part. Underside of prosoma is steel black, opisthosoma with strong buff color and pronounced patch. The specimen was a large gravid female with a U-shaped vulva composed of symmetrical two-sided pieces being narrower in front marked with a median sclerite. It lacked the right pedipalp and right leg of the fourth pair (Fig. 2). After observation, the specimen was released into its natural habitat. There are 18 species of spiders known to endemic among 50 recorded species; however, arachnology in Bangladesh is still in its sprouting stage (Siliwal and Molur 2006). Owing to the high rate of endemism, the discovery of O. lamarcki from the remote sandy-loamy island of Nijhum Dwip of the young lower Meghna estuary accounts the rich, still-to-be-described and little-studied invertebrate diversity of the country (Fig. 1). Acknowledgements: The authors are grateful to ECOFISH Bangladesh Project, World fish and IUCN Bangladesh Country Office to create the sphere of this discovery.

LITERATURE CITED AHMED, A.T.A., KABIR, S.M.H., AHMED, M., RAHMAN, A.K.A., HAQUE, E.U., AHMED, Z.U., BEGUM, Z.N.T., HASAN, M.A. and KHONDOKER, M. (eds.). 2008. Encyclopedia of Flora and Fauna of Bangladesh (Arthropoda: Arachnida). Asiatic Society of Bangladesh, Dhaka. Vol. 18(1), 309-14. BISWAS, V. and RAYCHAUDHURY, P. 2005. Huntsman spiders of Bangladesh: Genus Heteropoda Latreille and Olios Walcknaer (Araneae: Sparassidae). Rec. Zool. Sur. Ind. 104(3-4): 103-109. FOELIX, R.F. 2011. Biology of Spiders. Oxford Univ. Press, New York. 419 pp. GRAVELY, F.H. 1931. Some Indian spiders of the families Ctenidae, Sparassidae, Selenopidae and Clubionidae. Rec. Ind. Mus. 33: 211-282. ISBISTER, G.K. and HIRST, D. 2003. A prospective study of definite bites by spiders of the family Sparassidae (huntsmen spiders) with identification to species level. Toxicon 42 (2): 163-171. KESWANI, S., HADOLE, P. and RAJORIA, A. 2012. Checklist of spiders (Arachnida: Araneae) from India. Ind. Journ. Arachn. 1(1): 1-129. PLATNICK, N.I. 2011. The World Spider Catalog. American Museum of Natural History, New York. Ver. 12. http://re § € arch. amnh. org/entomology/spiders] catalogl index. html (accessed on 24February 2017). POCOCK, R.I. 1901. Descriptions of some new species of spiders from British India. J. Bombay Nat. Hist. Soc. 13(3): 478-98. SETHI, V.D. and TIKADER, B.K. 1988. Studies on some giant crab spiders of the family Heteropodidae from India. Rec. Zool. Sur. Ind. 93: 1-94. SILIWAL, M. and MOLUR, S. 2006. Checklist of spiders (Arachnida: Araneae) of South Asia including the 2006 update of Indian spider checklist. Zoos’ Print. 22(2): 2551-2597.

(Manuscript received on 19 March, 2017; revised on 24 April, 2017)